Frequently Asked Questions

1. Incubation and Embryology FAQ's

   1a. Poultry Industry and Production Questions

   2a. Breeds of Chickens

   3a. Egg Grading and Candling

2. Incubating Your Eggs

3. FAQ's on Candling

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1. Incubation and Embryology FAQ's

Poultry Industry and Production Questions:

1. Why do brown shelled eggs cost more than white shelled eggs?

Brown shelled eggs cost more because the chickens that produce these eggs eat more feed and production costs are more.

2. Why are brown shelled eggs bigger than white shelled eggs?

Brown shelled eggs are bigger than white shelled eggs because they are produced from a dual purpose breed (eggs - meat) that is larger in size (6-7 lbs.) than a Leghorn breed that is smaller in size (3-4 lbs).

3. Does the time of the year affect the fertility rate?

Extreme cold (winter) or extreme heat (summer) can lower fertility rate dramatically.

4. How many females can one male service?

One male egg producing chicken (Leghorn) can service 10 - 15 females. One male dual purpose chicken (Rhode Island Red) can service 6-8 females.

5. What is the average life of the male chicken?

A male chicken would live on the average of 3-5 years.

6. How large are female chickens?

A female White Leghorn is about 4 lbs. and a female Rhode Island Red is about 6-7 lbs.

7. How can you tell a hen from a rooster?

Difficult to tell at hatch unless they are feathersexed (female primary feathers are longer at 3-4 days of age). In adults, males are larger with longer wattles and larger combs.

8. Do you need sunlight to formulate hard shells on eggs?

No. An adequate source of calcium in the diet is needed.

9. Do chicken houses need to be heated?

No. Usually chickens in large commercial houses provide their own heat.

10. How much light is needed in the chicken house?

Only enough light is needed to read a newspaper at arms length (about 1 foot candle).

11. When does production begin?

At sexual maturity. This is about 17-18 weeks of age for the female hen.

12. What factors affect egg production?

Many factors affect egg production. The most important are diet (nutrition), temperature, humidity, length of artificial light (14 hours of constant light is recommended), and other nutritional and environmental factors.

13. How long does it take to raise a fryer?

About 42-49 days; six to seven weeks to market weight of 4.5 lbs.

14. What is a blood spot?

A blood spot occurs from a broken blood vessel across the stigma line on the yolk follicle when the yolk is released into the reproductive tract.

15. What is a meat spot?

A meat spot occurs when a part of the oviduct peels off when the egg is formed.

16. Is there one kind of egg carton that is better than another?

A styrofoam carton is preferred to a paper carton because it protects the eggs better.

17. How long does it take to put the shell on the egg?

It takes about 20-22 hours for the shell to be deposited around the yolk and albumen. This occurs in the uterus or shell gland.

18. What is salmonella?

Salmonella is a bacteria that can form on the outside of the shell when an egg or its contents become contaminated. It can cause food poisoning if eggs are not properly handled and cooked.

19. What are the critical issues related to salmonella?

Eggs and other food should be properly handled and cooked. Salmonella poisoning is not a problem if food products are properly prepared.

20. How often are eggs infected with salmonella?

It has been shown that possibly one egg in one million eggs produced may have some salmonella growing inside an intact egg.

21. What is the proper way to cook an egg?

Eggs can be cooked in many different ways. Thoroughly cooked eggs include: eggs cooked until the whites and yolks are not runny, hard-cooked eggs, baked eggs, and other egg-rich foods cooked to an internal temperature of at least 106 degrees F.

22. Do brown eggs have more cholesterol than white eggs?

Brown and white shelled eggs have the same amount of cholesterol (200-210 mg per egg).

23. How many eggs does a chicken lay per year?

250-270 eggs per year.

24. What causes a double yolk egg?

The release (ovulation) of two yolks from the ovary simultaneously. It is abnormal and does not occur very often, but will occur in a hen's egg production cycle.

25. Is the shell hard or soft when laid?

The egg is hard when laid by the hen.

26. How is the egg fertilized?

When the rooster inseminates the hen, the male sperm swim up the reproductive tract and localize in sperm host glands in the infundibulum. When a yolk is released one sperm penetrates the germmal disc and fertilization has begun.

27. When do the chicks need water?

Immediately. The chicks need to drink water when they are transferred to the brooder box.

28. When do they need food?

The chick needs food probably the first day, but can survive for up to 3 days after hatching.

29. What are hackle feathers?

Hackle feathers are neck feathers on a chicken. A rooster has long pointed ones, and the female has short rounded ones.

30. What are saddle feathers?

Saddle feathers are feathers toward the tail end of the chicken. A rooster has long pointed ones, and the female has short rounded ones.

31. Can you tell the sex of the chicken from the feathers alone?

Yes, if the breed is feathersexed. The female chicks' primary feathers will be longer than the males. It is difficult to tell the sex of a newly hatched chick if the breed does not have the feathersexed characteristic.

32. Is there a pecking order?

Yes, within a group of chickens from two to hundreds they establish a pecking order of dominance.

Breeds of Chickens

33. Why are brown shelled eggs bigger than white shelled eggs?

Brown shelled eggs are bigger than white shelled eggs because they are produced from a dual purpose breed (egg-meat) that is larger in size (6-7 lbs.) than a Leghorn breed that is smaller in size (3-4 lbs).

34. How do you know what color shell the eggs will have?

The earlobes of the chicken dictate the color of the shell (white ear lobes = white eggs; red earlobes = brown eggs).

35. What kind of chicken lays green eggs?

An Aracona chicken lays green shelled eggs.

Egg Grading and Candling

36. What is the weight of jumbo, extra large, large, medium, small and pee wee eggs?

Jumbo - 30 ounces per dozen
Extra Large - 27 ounces per dozen
Large - 24 ounces per dozen
Medium - 21 ounces per dozen
Small - 18 ounces per dozen
Pee Wee - 15 ounces per dozen

37. What are the egg grades?

Egg grades are:

• AA - shell-clean, air cell-1/8" or less in depth, white-clear and firm;

• A-shell-clean, air cell 3/16" in depth, white-clear; and

• B-shell-clean to slightly stained, air cell over 3/16" deep, white-weaker and watery.

38. What is a leaker?

A leaker is a broken egg where the contents leak out of the shell.

39. What is candling?

Candling is shining a bright light near the egg to determine the egg quality and also embryonic development.

40. When should the eggs be candled?

Eggs can be candled anytime after about Day 5 of incubation through Day 17.

41. How many eggs should be candled at a time?

Out of 2 dozen eggs in the incubator, probably no more than 5-7 eggs should be candled at one setting.

42. How long should the eggs be out of the incubator?

No more than 5 to 10 minutes at a time.

Incubation

43. What is the best temperature for storing eggs?

Egg should be stored between 55 and 60 degrees F.

44. How much humidity is needed?

Enough humidity is needed to maintain a wet bulb temperature of about 85 to 87 degrees F (50-55 percent relative humidity). This is normally attained if water channels in incubator are kept full.

45. How do you disinfect the incubator?

Disinfect incubator with 10 percent bleach solution, then wash with warm soapy water and rinse thoroughly.

46. Does when the egg was laid affect the hatch date?

No. If fertile eggs are stored properly (55-60 degrees F) then hatch date for the chicken will be about 21 days following the time they are placed in the incubator.

47. When should the incubator be prepared for the eggs?

About one week before starting the incubation process.

48. Where should the eggs be stored, if they cannot be set right away?

If they cannot be put in an incubator right away, then they should be kept in a cool room at a temperature of 55-60 degrees F.

49. What is the longest eggs should be held before incubating?

No more than seven days.

50. What is the correct temperature for incubating fertile eggs in a still air incubator?

Optimum temperature is 100.5 degrees F.

51. What is the temperature range that is acceptable during incubation?

Temperature range is 99 -103 degrees F.

52. What is the lowest temperature?

Lowest temperature should be 99 degrees F.

53. What is the highest temperature?

Highest temperature should be 103 degrees F. Never keep at 103 degrees F for more than than a few hours.

54. How do you check the accuracy of the incubator thermometer?

Accuracy of an incubator thermometer can be checked by placing a medical thermometer and an incubator thermometer in a pan of 100 degree F water, or take a good thermometer from the science storeroom and place it next to the incubator thermometer in the incubator at 100 degree F.

55. When should the plugs be removed from the incubator?

Remove plugs (air holes) from the top of the incubator when you see the chicks start to hatch.

56. What are the factors for success?

• Successful hatches can be obtained by:

• Securing fertile eggs

• Maintaining the correct temperature

• Maintaining correct humidity levels

• Increasing ventilation when chicks hatch

• Turning the eggs properly

57. What should be used to mark the eggs?

A lead pencil only.

58. Do I need to take the eggs home for the weekends?

Yes, it is encouraged to take eggs home on the first two weekends to turn the eggs and regulate temperature.

59. How do I transport the incubated eggs from school to home and back?

Carefully. Put the eggs in a styrofoam egg carton and wrap the carton in a blanket; or leave eggs in the incubator and place a blanket over them so they won't roll around.

60. Where should the eggs be placed in the car when taking them home?

Place the eggs on the front floor on the passenger side and turn on the heat.

61. What is the normal hatch time for a fertile incubated egg?

Normal hatch time for chicken eggs is 21 days.

62. What will delay the hatch?

Too low of an average temperature will delay the hatch.

63. Why are the chicks sometimes very wet and mushy?

Chicks are wet and mushy if too much humidity is in the incubator. To lower humidity at the end do not place more than one sponge in bottom of incubator.

64. How can I be sure that I have enough humidity?

If the proper water level is maintained in the bottom of the incubator the correct humidity should be maintained.

65. How can I tell if I have too much humidity?

If there is a lot of condensation on the inside of the incubator windows, then there is probably too much moisture in it. This is usually not a big problem.

66. How long should I leave the eggs in the incubator if they do not hatch on the twenty-first day?

Leave the unhatched eggs until the 23rd or 24th day.

67. What causes deformed legs?

Deformed legs are caused by poor nutrition of the hen. Other factors are disease, contamination and improper temperature.

68. How do I add water?

Add warm water (100 degrees F) with a squeeze bottle, or meat baster; do not get eggs wet.

69. How do I count the days?

Count the days of incubation from the first day the eggs are placed in the incubator. If placed in the a.m. that day would be Day 1; if placed in the p.m. that day would be Day 0, the next day would be Day 1.

70. When do I stop turning the eggs?

Stop turning the eggs on Day 18.

71. When should I put the crinoline on the wire grate?

Put the crinoline (cheese cloth) on the wire grate of the incubator after Day 17 or on Day 18.

72. How can I add additional humidity?

Add additional humidity on Day 18 by placing 2-3 wet sponges on the bottom of the incubator.

73. What should I do if the chicks do not fluff up?

If chicks do not fluff up remove sponges from the incubator and water from the channels.

74. What is the brooder box?

A brooder box is a temporary home for baby chicks up to one week of age. It contains 2-3 inches of litter, a feeder, and water. It also includes a heat source suspended above the box.

75. How do I make a brooder box?

Take a cardboard box (2' x 3' x 1') and place items mentioned in answer 74.

76. What should be used in the bottom of the brooder box?

Use soft pine-wood shavings, untreated cat litter, sand, rice hulls, or ground corn cobs, but not newspaper.

77. Do the teachers need to teach the chicks to drink and eat?

Yes, it would be a good idea to dip the baby chick's beak in the feed and water so they know where it is.

78. Should you help a chick out of the shell?

No, if the chick can not come out of the shell on its own then it is a weak chick and probably would not survive.

79. Where should the thermometer be placed in the incubator?

On the wire grate away from the heat source and in the center of the incubator.

80. What is the function of the air cell?

The air cell function is to provide the chick with air when it first starts to break open the shell.

81. What is the critical period in hatching?

The first 3-5 days and Days 18 and 19. When the embryo is forming early on and when it gets in position to hatch.

82. How often should the eggs be turned?

Eggs should be turned at least three times a day.

83. What happens if the eggs are not turned?

If eggs are not turned, the embryo will die about Day 11.

84. What causes the embryo to develop fully, but not pip the shell or hatch?

Too low or too high temperature, to too low or too high humidity.

85. Do you need to do anything to prevent the chicks from drowning?

Place marbles or rock in the water pan in the brooder box to keep chicks from drowning.

86. Why do chicks stick to the shell?

Too low humidity during incubation.

87. What causes the navel to be sore?

Too high temperature during incubation, excessive humidity near the end of incubation, or infected embryo early in incubation.

88. What should you do if the chicks pick at one another?

Separate them from each other in the brooder box, or construct another brooder box and separate the chicks.

89. Can chicks be marked?

Yes.

90. How do you color embryos?

To color embryos you inject a colored dye about .2 to .5 milliliters into the egg with a hypodermic needle near the bottom of the egg.

Embryology

91. How do you preserve embryos? Using formalin or glycerine and ethyl alcohol?

Embryos can be successfully preserved by storing them in an alcohol solution (3-4 drops of glycerine on embryo), then immerse in 70 percent alcohol (14 parts of 95 percent ethyl alcohol to 5 parts of water).

92. What is the correct procedure for breaking out an embryo?

Break open the shell on the large end of the egg, then pour out the liquid contents and carefully drop the embryo on a pie tin.

93. How long does it take to pip the shell completely?

Two to four hours.

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2. Incubating Your Eggs

1. How must I store eggs?

Your eggs need to settle for at least 24 hours if they came through the post. This allows the air cell inside the egg to return to it's normal size. Eggs should always be stored with the pointy end down while they are "in the hold". It's a good practice to follow and it will help your hatch!

If you receive eggs that are getting old, you may only let them settle overnight.

2. When is my incubator ready to start incubating?

By the time you have gotten your eggs your incubator should have been running at least 24 hours. A week is even better. This gives you time to learn what's going to happen in your incubator and allows you to make any necessary adjustments before setting your eggs. A surefire way to ruin hatching eggs is to put them in the incubator without having it properly adjusted.

Take note of the term "internal" temperature. Don't confuse internal egg temperature with internal incubator temperature. The temperature in an incubator changes constantly, rising and lowering. The temperature inside the egg will be an average of this temperature swing in your incubator.

3. What must the temperature and humidity be inside my incubator?

This is plain and simple, yet the MOST important part of hatching.

Fan Forced incubator: 37.5 degrees C measured anywhere in the incubator.

Humidity: 55% for the first 18 days, 60-65% for the last 3 days in the hatcher.

4. Is my thermometer accurate?

Thermometers go bad. Keeping the temperature accurate can be a struggle, even with very good thermometers. A nice part about running a big incubator over an extended period is that you can tweak the temperature regardless of what thermometers tell you.

After the first hatch, you can raise or lower the temperature by what the hatch tells you. If they hatched early the temperature needs to be lowered. If they hatch late the temperature needs to be raised.

You can check your Thermometer this way. Keep notes on everything you do during the incubation period. As you learn you'll have these notes to look back on. They will be the most valuable tool that you can have. It won't be long until you can say "I know what happened, all I need to do is change this one little thing". Soon you will be able to make adjustments by knowing what to do, instead of guessing!!!

5. How do I check humidity?

Humidity is checked by way of a hygrometer (wet-bulb thermometer) in conjunction with a regular "dry-bulb" thermometer. A hygrometer is simply a thermometer with a piece of wick attached to the bulb. The wick hangs in water to keep the bulb wet (hence the name "wet-bulb thermometer"). When you read the temperature on the thermometer and hygrometer, you must then compare the readings to a chart to translate from wet-bulb/dry-bulb reading to "percentage humidity".

From the relative humidity table, you can see.....

60% humidity reads about 30.5 degrees C on a wet-bulb at 37.5degrees C.

60% humidity reads about 31.6degrees C on a wet-bulb at 38.6degrees C.

80% humidity reads about 33.8degrees C on a wet-bulb at 37.5degrees C.

80% humidity reads about 35degrees C on a wet-bulb at 38.6degrees C.

Getting your humidity to become as accurate as your temperature is nearly impossible. It is almost completely impossible with a small incubator. Try to get your humidity as close as you can, and you'll be fine. Just being aware that humidity is important, and trying to get the numbers to come in close will be a huge help to your hatch.

If you can hold within 10-15% things should turn out fine.

Temperature on the other hand, is CRITICAL!!!!! I hate to beat this point to death, but a small deviation in temperature (even a couple degrees) can and will ruin a hatch. Or, at least turn a potentially great hatch into a lousy one.

6. An important point about incubator humidity

As seasons change, so goes humidity. When you are incubating eggs in January and February it will be very difficult to maintain a humidity that is as high as you like. That's because the outside humidity is so low.( Depending on where you live). By the same token, when you are incubating in June and July the outside humidity is usually much greater and the humidity in your incubator will most likely get much higher than you would like. Hatching problems will change as the season progresses. If you are doing things the same way in July as you were in January, you have to expect different results. All I am trying to say here is that your incubator humidity changes directly according to the outside humidity. Low outside, low in the incubator. High outside, high in the incubator. To adjust for these problems, you need to change the surface area of water in your incubator.

7. What is surface area?

Surface area is "the amount of surface of water exposed to air in your incubator". The depth of water has absolutely no bearing on the humidity in the incubator (unless the depth is zero). If the humidity is too low in your incubator, add surface area. Place another pan of water in the incubator, or some small, wet sponges. This will help. To decrease the humidity, remove surface area. Use smaller containers of water, or undo some of the things you've added.

8. How long will it take to incubate chicken eggs?

The incubation period for chicken eggs is 21 days. You should turn your eggs at least three times a day for the first 18 days, and stop turning after the 18th day (or use a hatcher if you have eggs from different days in the same machine). This allows the chick time to orient itself inside the egg before pipping.

After day 18, KEEP THE INCUBATOR CLOSED except to add water. This will help bring the humidity up to help the chicks hatch. I know it will kill you not to open the incubator 1000 times when it's this close to hatch time, but it's not good for the chicks. If you haven't bought an incubator yet, invest the extra couple bucks in the picture window model. Then you can "see it all" without causing harm to your hatch.

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3. FAQ's on Candling

1. Will all the eggs in my incubator hatch?

It is probable that only 90 percent or less of incubated eggs are fertile. (Not all 90% of eggs will hatch either).
Removal of eggs that can be identified as infertile or dead eliminates possible sources of contamination from the incubator.

Candling can be used to identify some of these eggs.

Shining a light through the egg to observe embryo development is called candling

White or pale eggs are more easily candled than dark or speckled eggs. Many people use small flashlights with lenses that can be focused to candle eggs.

Excellent candlers also can be purchased at a reasonable cost. Simple candling devices can be made by inserting a light into a container and cutting a small hole to emit light, or by taping a cone formed from several thicknesses of paper over the lens of a bright light projector. The hole that allows light to pass from the tip of the cone should be dependant upon the size of the egg.

In a dark room, hold the egg to the light of the candler to observe the contents of the egg. Cooling that occurs for short periods (less than 10 minutes) during careful examination of eggs does not harm the development of the embryo. However, limit the exposure of the egg to the hot light source.

The presence of embryos can be confirmed easily after 8 days to 12 days of incubation.

The embryo is located in the large end of the egg, where blood vessels radiate under the surface of the shell. The embryo appears as a dark spot that becomes larger as incubation progresses. Eventually only a dark mass and the air cell are seen. An infertile or unincubated egg brightly transmits light in comparison. Remove infertile or non-growing eggs from the incubator. If questions arise about candling, contact someone with experience for advice.

Dead embryos will sometimes appear as a ring or smear of blood in the egg or a dark spot dried to the inside of the shell. The living embryo will appear as a dark spot in the large end of the egg surrounded by a faint outline of blood vessels. The blood vessels will appear firm and distinct. After embryo death, the embryo no longer grows and the blood system fades.

Retain records of egg infertility or embryo death. Some mortality can be expected, however, unusual occurrences of mortality or certain characteristics of the mortality can be indicators of practices that can be corrected to improve hatchability.

2. How do I candle eggs?

Shine a bright light through the egg. Candling is not a specific art.

It is more of a comparison, meaning all the eggs of the same age should look the same. It is something best learned by doing it, and really is just as simple as you make it. You cannot hurt eggs by candling them (short of dropping them). They can be out of the incubator for a half-hour without any harm. Candle every day if you like, after day 3 you should see something. At about 8 days, you can see the chick wiggling and kicking in his egg.

3. How do I spot bad eggs?

The egg on the left shows a ring at 6 days. This ring is formed by concentrated bacteria which has invaded the eggs' membrane. It can become present very early, or after the chick has already started to form, as in the picture on the right. In the picture on the right the ring, or portion of it, can be seen at the bottom of the egg with the expired chick in the middle.

For a different reason. The egg on the left shows a blood spot. In my experience an egg with a blood spot will not hatch. They will go bad and blow up, though. The egg on the right at 6 days shows "clear". It is infertile, or too old to germinate.

The egg on the left shows a blood spot incubated to 8 days. You can see the bacterial ring forming at this point. Soon this egg will start to "weep", and if it isn't caught in time, it will explode into a stinky mess. The egg on the right shows highly defined pores. Eggs that look like this under candling have a slim chance of hatching in my experience. I've noticed that it mostly depends on the severity of the porosity.

On the left, you can see the "spider" of veins growing away from the peep. This egg is at 6 days. You can see this spider in a smaller version at 3 days. The egg on the right is at 2 weeks. You can see the clear spot beneath, with the yolk and peep floating at the top.

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